On Feb. 13, MacDonald (14-1 MMA, 5-1 UFC) suffered a severe neck and back strain that will sideline him for two to three weeks and prevent a rematch with Carlos Condit (28-6 MMA, 5-2 UFC), whom he was set to fight next month at UFC 158.

“Rory is very upset that he will not be able to face Carlos, but he’s looking forward to getting back to training as soon as possible,” wrote MacDonald’s manager, Lex McMahon, in a prepared statement.

Zahabi, though, said it’s far too early to tell when MacDonald will be back in the cage.

“Now, I just want him to focus on rehabbing his injury, coming back slow and building up the pace,” he said. “This is part of fighting. People get injured, but we have to try to keep it at an absolute minimum. It’s a big challenge.”

And there have been many. Just this past year, Zahabi watched as his star pupil, St-Pierre, battled back from an ACL injury suffered in training. After a long rehabilitation, the champ returned three months ago at UFC 154 to successfully defend his belt against Condit.

MacDonald is widely considered to be an heir to St-Pierre’s throne, though the 23-year-old said he’ll move up in weight or fight other opponents rather than face his teammate, who mentored him at Zahabi’s Tristar gym when he moved from his longtime home in the Canadian city of Kelowna to Montreal.

But MacDonald isn’t moving anywhere, literally and figuratively, as injuries mount. UFC 158 is the fourth scheduled event within three years that he’s been forced out of due to one ailment or another.

Although he recently changed his nickname to the more serious “Ares,” MacDonald’s teammates called him “The Waterboy” after the fictional movie character that rages on the football field.

“He’s too aggressive,” Zahabi said. “I really try to hold the reigns. I tell him, ‘OK Rory, we’re going to do less today,’ and we always end up doing more. Emotions get in the way, and he wants to spar more.”

That makes Zahabi’s guidance all the more important for MacDonald, whose age should put him close to the peak of his physical abilities.

“I lecture him all the time: You’ve got to go slow and steady, and gradually increase the intensity closer to the fight,” Zahabi said. “The body can only take so much. And don’t forget, he started very young. That’s one of the side effects of athletes that start when they’re young. They have a young body with a lot of miles.”

Zahabi doesn’t underestimate the toll taken on MacDonald following a previous fight with B.J. Penn, which lasted three rounds despite a dominant win, or the effect a quick turnaround for Condit may have had.

The trainer is trying to get his fighter to take a measured pace.

“It’s something that Georges learned over time,” Zahabi said. “He’s a lot more sensible, and sometimes you’ve just got to learn the hard way, and I think Rory is starting to understand. I had a long talk with him, and I told him he has to respect his body and how his body feels.”

Zahabi is relieved that doctors haven’t found more serious damage to MacDonald than a neck strain. At this point, the fighter is not allowed to do anything more than walk for the next two to three weeks, after which he’ll ease back into technique-only training.

It could take longer to get back to sparring and preparing for an opponent, but Zahabi, who himself spent two months on the bench with a similar injury, said it’s a relatively small price to pay.

“Your neck is something valuable,” he said. “I was scared he had a tear in his neck or something serious. No ligaments were torn, and nothing is fractured. I’m happy that it’s not worse.”

As the UFC 189 tour made its last stop in Dublin, featherweight champ Jose Aldo was met with a torrent of abuse from the Irish fans. It might have been unpleasant, but it might also have been just what he needed.